Filled hollow structure and tool for manufacturing same

ABSTRACT

A filled hollow structure includes an open hollow structure from a first material. The open hollow structure is at least partially closed by a closing structure. The hollow structure is filled with a filler medium. The filled hollow structure is overmoulded with a second material.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.13/705,787, filed Dec. 5, 2012, which claims the benefit of U.S.Provisional Application No. 61/566,850 filed Dec. 5, 2011, the entirecontents of each of which are hereby incorporated by reference in theirentirety.

FIELD OF THE INVENTION

The invention relates to a method for producing a filled hollowstructure and more particularly to a method for producing a closed, andfilled hollow structure with a complex geometry. Furthermore, thepresent invention relates to a filled hollow structure and moreparticularly to a closed, and filled hollow structure obtainable by amethod according to the present invention as well as to a tool forproducing such filled hollow structure and/or to using said tool forperforming a respective method.

BACKGROUND OF THE INVENTION

Hollow structures are known in the prior art, for example, in the fieldof face masks for delivering breathable gas or fluid to a patient. Insuch face masks, hollow cushions are used for providing contact zonesfor contacting the face of the user in order to improve comfort bymoderating or otherwise distributing contact force. Furthermore, suchstructures are used as a sealing structure for sealing the mask interiorfrom the exterior in the contact region where the mask rests on a user'sface.

A disadvantage of hollow structures known in the art is that they arecomplicated to manufacture and numerous manual manufacturing steps areoften necessary. Moreover, such hollow structures are either not closed,i.e., open, or are closed in an ineffective and/or complicated manner.

In particular, it is known to fill a mask cushion with silicone or gelwherein the hollow structure is closed by use of a silicone adhesive.

The solutions known in the prior art are in particular, not easy tohandle, not durable, complicated and expensive to manufacture, notsuitable for automating, not bio-compatible as well as optically andhygienically objectionable.

WO 2008/089799 discloses an improved method for producing a filledhollow structure by producing an open hollow structure of a firstmaterial, positioning the open hollow structure on a tool adapted tohold the open hollow structure, filling the open hollow structure with afiller medium, and then closing the filled open hollow structure with asecond material.

SUMMARY OF THE INVENTION

One aspect of the present technology relates to a method for producingor manufacturing a filled hollow structure and particularly a filledhollow structure which overcomes the deficiencies of the prior art. Moreparticularly, an aspect of the present technology relates to a methodfor manufacturing the filled hollow structure which is easy andefficient to carry out, which can be automated, and which provides for adurable as well as an optically and hygienically improved hollowstructure. Moreover, an aspect of the present technology relates to atool for producing a hollow structure as well as to an improved hollowstructure.

Another aspect of the present technology relates to a method forproducing a filled hollow structure, comprising the production ormoulding of an open hollow structure or bladder of a first material(e.g., a structure having an opening) the structure having a hollow or ahollow area such as a pocket or a cavity, wherein at least a portion ofthe hollow is open towards the outside of the structure; providing aclosing structure to at least partially close the open hollow structure;filling the hollow structure, with a filler medium; and overmoulding thefilled hollow structure with a second material. Preferably, filling ofthe hollow structure may be at least partial.

Another aspect of the present technology is that it simplifies and ormakes practical the filling of a complex cushion shape, for example acushion geometry with a non-planar cushion-to-frame side.

According to the present technology a filler medium is preferablyconsidered to be a medium being non-releasably contained in a structure,i.e. a medium which is to stay in a structure, such as a hollowstructure. According to the present technology a filled hollow structureonce overmoulded is preferably considered to non-releasably contain thefiller medium.

According to the present technology a closing structure may be an inlay,a cap, a plug or the like that at least partially, mostly or entirelycloses the open hollow structure, preferably in the area of thestructure's opening. Preferably, provision of the closing structurecloses the open hollow structure while maintaining the hollow or cavity.The hollow or cavity is then, preferably, filled with a gaseous mediumsuch as gas or fluid. Therefore, providing a closing structure maycomprise inserting a plug or an inlay into, preferably the opening of,the open hollow structure. The plug may fit snugly into the opening ofthe open hollow structure. In an embodiment of the present technologythe plug may be preformed. However, alternatively or additionally, aplug may also be moulded onto and/or into the open hollow structure. Inthis context, it is to be noted that a closing structure as referred toin the present application is preferably a comparatively stiff or rigidelement while not being limited thereto but may also or alternatively beat least partly elastic, pliable and/or flexible or the like.

According to the present technology the hollow structure may be filledafter closing the open hollow structure with the closing structure. Thisis, the open hollow structure may be first closed and/or sealed with theclosing structure, as discussed above, and subsequently at leastpartially filled with a filler medium. Therefore the closing structureprovides at least one filling structure for filling the open hollowstructure with the filler medium and/or at least one gas or fluidevacuation structure. Such structures may be closed but openable, suchas piercable by means of gas or fluid pressure and/or a filling needle.In preferred embodiments of the technology, the hollow structure,therefore, may be filled through a hard or relatively hard closingstructure that will not deform under the pressure or force from thefilling material. Alternatively or additionally, the closing structuremay be provided with at least one opening or hole for filling the openhollow structure with the filler medium and/or at least one opening orhole for gas or fluid evacuation. The closing structure may be a plug.

According to the present technology the hollow structure may becompletely or partially filled with the filler medium. For example, inone form the filler medium may be injected.

In an additional step, a vacuum may be applied to the hollow before thefiller medium is inserted into the hollow. The application of the vacuumto the hollow sucks gas or fluid out of the hollow before the fillermedium is inserted into the hollow so that an improved, e.g., void free,filling of the hollow may be achieved. The application of vacuum and thefilling may be carried out subsequently and/or simultaneously. Theapplication of a vacuum may be advantageous in case, e.g., a viscous gelis used as a filler medium. In a further additional step, a vacuum maybe applied to the hollow and the filler medium after the open hollowstructure has been filled with the filler medium. This step may improvethe optical and hygienically appearance of the filled hollow structureas well as its mechanical properties by reducing or eliminating voidsoccurring in the filler medium and by providing a desired shape orstructure to the hollow structure. The hollow structure may comprise aconnection adapted to allow pressure or a vacuum to be applied to thehollow structure. The connection may allow the vacuum to shape thestructure and to fix the respective shape. In an embodiment, theconnection may be closed or be adapted as a one way valve so that thevacuum may be maintained inside the hollow structure. The closingstructure may be embodied as a connections structure.

According to the present technology the hollow structure may beovermoulded after closing the open hollow structure with a closingstructure and filling the hollow structure with a filler medium. Theclosing structure may be adapted to substantially or completely inhibitcontact between a second material used for overmoulding the closed andfilled hollow structure and the filler medium and/or to separate orspace apart such second material and the filler medium when the filledhollow structure is overmoulded. The filling structure, such asmembrane, opening and/or hole of the closing structure may be closed byadditional material and/or additional structures for this purpose and/orbe designed to avoid contact of the filler medium and the secondmaterial.

The open hollow structure may be made of a flexible first material,e.g., a plastic or synthetic material such as an elastomer material or amaterial comprising elastomer components. For example, the firstmaterial used to produce the open hollow structure may be silicone suchas liquid silicone rubber (LSR), or thermoplastic elastomer (TPE). In anembodiment, an open hollow structure may be an injection moulded plasticskin, e.g., made of silicone or a liquid silicone rubber (LSR).

In an embodiment, the hollow structure may include a first portion to befilled by filler medium, a second portion which is constructed toincorporate the closing structure and a third portion which is adaptedfor being overmoulded with the second material. Alternatively, the thirdportion may be optional and the hollow structure may comprise only thefirst and the second portions while the second portion comprises asealing area that is adapted to form a seal along the perimeter of theinner and outer walls of the open hollow structure with the closingstructure when said closing structure is inserted and/or overmoulded.

Furthermore, the hollow structure may have the general shape of abladder and may include thin or skin-like outer walls which may have,according to embodiments, a differing wall thickness and/or topography.According to an embodiment, the open hollow structure may be describedas having a tube-like structure bent to form a hollow structure havingan inner wall and an outer wall which merge at one end of the structurevia a bottom or transition wall and which is open at the other end ofthe structure. However, it is to be understood that the tube-like basicform as referred to above is not restricted to one diameter or acircular form but may comprise different cross sections, diameters, wallthicknesses, etc. The tube like structure may have been given asubstantially triangular shape when seen from the top and/or the bottom.In an embodiment, when used in the field of face masks for deliveringbreathable gas or fluid to a patient, the hollow structure may have agenerally tubular ring-like form with a generally triangularcross-section, particularly at its bottom or transition wall serving asa contact zone for resting on a patient's face. In an embodiment, whenused in the field of face masks for delivering breathable gas or fluidto a patient, the wall thickness may vary and may lie in the range ofabout 0.1 mm to about 7 mm. In an embodiment, the hardness of the hollowstructure may lie in the range from about 1 to 80 Shore A, e.g., about20 to 60 Shore A or in the range of about 3 to 10 Shore A or about 5Shore A or 40 Shore A. The hardness may depend on the spring and dampingproperties of the material and the ability to be easily demoulded.

According to the present technology the closing structure may be formedof a material suitable to snugly close and/or sealingly engage with theopen hollow structure, e.g., of silicone. In embodiments, there could bea mechanical or chemical bond between the closing structure and thehollow structure.

The filler medium which is filled into the open hollow structure mayinclude a fluid, i.e., a gaseous, dispersible and/or liquid fluid, anexpandable fluid, foam, a powder and/or gel, preferably of silicone,oil, high viscosity fluids, wax, and/or low hardness elastomers.According to embodiments, a mixture of the above media may be used,e.g., two gels of different hardness or viscosity.

The second material may be a material suitable for overmoulding thefilled hollow structure, preferably, a material suitable forovermoulding the closed and filled hollow structure. This again may be aflexible first material, e.g., a plastic or synthetic material such asan elastomer material or a material comprising elastomer components.Preferably the material is mouldable. For example, the second materialused to overmould the filled hollow structure may be silicone, LSR, orTPE, TPU, TPV or comprise any of these materials. The second materialmay be provided as a gel or foam. In an embodiment, the second materialmay be or include the same material as the first material but differentmaterials may also be provided. In particular, differing hardness ofotherwise similar materials may me used as first and second materials.If completely dissimilar materials are used, they preferably are chosensuch that they adhere to or are compatible with one another. The filledhollow structure may be overmoulded by injection moulding.

The closing structure may have a hardness that is higher than thehardness of the first and/or the hardness of the second material. Inpreferred embodiments of the technology the hollow structure, therefore,may be filled through a hard or relatively hard closing structure thatwill not deform under the pressure or force from the filling material.Materials having desired properties are, inter alia, disclosed in WO2009/062265 A1 and WO 2009/143586 A1, which are hereby incorporated byreference in their entirety.

According to the present technology the filled hollow structure may beproduced by multi-component injection moulding. The open hollowstructure may be produced or moulded in a cavity of a moulding tool andmay remain in a mould half thereof when being closed and/or when beingfilled and/or when being overmoulded. In an embodiment, the hollowstructure is moulded, closed, filled and overmoulded while remaining ina mould half of a moulding tool. The tool may be a multi-componentinjection moulding tool.

According to the present technology any portion of a mould that forms amould together with an additional mould portion is considered a “mouldhalf”. Therefore, a mould according to the technology may compriseseveral, e.g., more than two mould halves and preferably comprises threemould halves. When three mould halves are provided, a first mould halfmay form a first suitable moulding cavity when combined with a secondmould half. A second suitable moulding cavity that is different from thefirst moulding cavity may be formed when the first mould half iscombined with a third mould half. A mould “half” may, thus, also bedenominated a mould “portion” in the context of the present technology.Alternatively there may be three or more mould halves which togetherform a moulding cavity.

In an embodiment, the open hollow structure may be held in the tool bythe provision of a firm fit by the application of compressed gas orfluid and/or vacuum. Parts can also be held in a tool by specificretention features, or simply by the geometry of the tooling cores andparting lines. Also, the closed hollow structure may be removed from thetool by the use of compressed gas or fluid and/or vacuum and/or ejectionpins.

In a further embodiment, the method according to the technology mayinclude coating the hollow structure particularly in order to improvedurability and/or optical and/or hygienically properties.

According to the present technology the filler medium may be structuredto harden and/or soften if certain predetermined conditions are met. Inan embodiment, the filler medium may harden and/or soften upon a triggersignal, such as a filling signal, or upon the application of heat orcold, etc. The filler medium may fill the open hollow structure quickerwhen softened and be more consistent.

It has been established that heating the tool used for moulding the openhollow structure and/or holding the hollow structure during filling,e.g. to about 130° C., may make it quicker to fill the hollow structureor bladder. Generally, and without wanting to be bound by a particulartheory, the speed at which the filler material enters the hollowstructure dictates the speed at which gas or fluid will exit the hollow.Thus, when the filler material enters the cavity fast enough, the thegas or fluid will evacuate the bladder quickly, which will positivelyinfluence the consistency of the fill.

However, if the filler goes into the bladder too quickly, the gases canbecome trapped in the filler as bubbles and lead to an uneven fill.Preferably balance between evacuating the gas and trapping gas bubblesis achieved. The evacuation structure (e.g. the opening for gas or fluidevacuation) may be sized to regulate the speed at which the gas isevacuated.

According to the present technology the filler medium may be at leastpartially cured. In an embodiment, the filler medium is cured in themould used for producing the open hollow structure. Such curing mayinvolve, depending on the conditions and the materials used, e.g., theaddition or removal of energy, application of temperature, i.e., heat orcold, radiation, e.g., UV-light, the addition of further substancesand/or time factors, i.e., waiting time, etc., foaming, and/orinitiation of crystallization.

The walls of the open hollow structure may act as an insulating layer toprevent the filler medium from curing in a hot tool to quickly, e.g.before the filler medium, such as a gel, has sufficiently spread throughthe bladder.

According to the present technology the method may further includeproviding a support structure between the filler medium and the secondmaterial. The support structure may also be provided between the closingstructure and the second material used for overmoulding the filledhollow structure. The support structure may be formed as a separateelement or integrally with the closing structure and may be at leastpartially, substantially or entirely overmoulded when overmoulding thefilled hollow structure with the second material.

In an embodiment, the support structure may substantially inhibitcontact between the second material and the filler medium. For thispurpose the support structure may cooperate with the closing structure.For example, the support structure may substantially obstruct at leastone opening and/or hole provided in the closing structure. Preferably,the support structure covers the closing structure and/or prevents thesecond material from encroaching on the filler medium.

According to an embodiment, the support structure may be a plasticsupport member. Preferably, the support structure is relatively rigid orrigid. The material used for the support structure is preferably harderthan the first material, the second material and/or the material usedfor the closing structure.

According to an embodiment, the support structure may include aconnection structure adapted to connect the filled hollow structure tofurther structures. For example, according to an embodiment, the filledhollow structure may form part of a breathing mask and thus may besuitable to be connected with other structures, to fulfill other oradditional functions, and/or to form additionally other structures sucha mask and/or in order to form a mask assembly including means forattaching such a mask to a patient's face. According to the presenttechnology the filled hollow structure may be a cushion for a breathingmask, particularly for providing a tight and comfortable contact betweenthe mask and a user. The connection structure may be adapted to connectthe hollow structure to the frame of the breathing mask and/or to ameans for attaching the mask to the patient's face, e.g., a headgear.Alternatively or additionally, the overmould may be adapted to connectthe hollow structure to the frame of the breathing mask or form such aframe. In an embodiment, the support structure comprises lugs forattaching the filled hollow structure to the frame of the breathing maskand/or to a gear, a headgear or other means for fastening such a mask tothe face of a patient. The breathing mask may be a nasal breathing maskor a full face mask.

Alternatively or additionally the support structure may be provided witha handling structure adapted for handling the support structure and/orthe hollow structure during manufacture. In this form, the presenttechnology advantageously facilitates robot assisted manufacture.

According to an embodiment, the second material for overmoulding thehollow structure may be of a functional nature. In the embodiment wherethe hollow structure defines a cushion of a face mask, particularly foruse in breathing therapy such as CPAP or VPAP™, the second material maybe formed as a frame or cushion clip structure to be connected to aframe.

Another aspect of the present technology relates to a filled hollowstructure produced by a method according to an embodiment of the presenttechnology as well as to a tool for producing such filled hollowstructure and/or for performing a method according to an embodiment ofthe present technology. The filled hollow structure comprises an openhollow structure from a first material that is at least partially closedby a closing structure and filled with a filler medium, the filledhollow structure being overmoulded with a second material. The closingstructure may be positioned between an opening of the hollow structureand the overmould so as to separate the filler medium and the overmouldapart. The overmould may be adapted as a functional structure.

The tool may comprise a first mould half, a second mould half and athird mould half. The first mould half is configured to form a cavitywith the general shape of the negative of an open hollow structure whenmating with the second mould half. This particularly allows the hollowstructure or bladder to be moulded. The first mould half is furtherconfigured to hold the open hollow structure while the open hollowstructure is at least partially closed with a closing structure andfilled with a filler medium. The third mould half is configured to forma cavity with the general shape of the negative of an overmould whenmating with the first mould half holding the filled hollow structure.The first and/or third mould is/are preferably adapted to additionallyhold and include the above discussed support structure. This preferablyallows the overmould to be specifically shaped on the closed and filledhollow structure. Preferably, the tool is adapted to and allows thehollow structure to remain in the first mould half during the subsequentproduction or method steps such as filling, closing and overmoulding.

According to another additional or alternative aspect of the presenttechnology a tool for producing a filled hollow structure by a methodaccording to an embodiment of the present technology comprises a firstmould half, a second mould half and a third mould half. The second mouldhalf is configured for producing an open hollow structure of a firstmaterial when being combined with the first mould half and the thirdmould half is configured for overmoulding the filled hollow structurewhen being combined with the first mould half holding the filled hollowstructure. The first mould half is configured to hold the open hollowstructure while the open hollow structure is at least partially closedwith a closing structure and filled with a filler medium. Furtheraspects of the present technology, relate to methods for using said toolin order to produce a filled hollow structure.

The closing structure provided according to the method of the presenttechnology may prevent the second material used for overmoulding thefilled hollow structure from encroaching the filler medium. Furthermore,the filling of the filler material into the hollow structure may bebetter controlled. For example, overflow air and gaps can be avoided.While the filler material may otherwise only fill up to a horizontal‘gravity’ line, the closing structure permits a non-horizontal ornon-planar fill.

Thus in accordance with the present technology, the filler material maybe added in an injection step as an alternative to a pouring step. Anadvantage of the technology is that it allows for filling of a complexthree dimensional shape, for example a non-planar shape. For example agel cushion for a full-face mask has a complex shape to effect a seal ona face in both the nasal bridge region and the chin region. The presenttechnology enables the manufacture of a full-face gel cushion thatfollows the complex three dimensional shape of the face and have, in oneform, a constant wall height of gel. In another form, the full face gelcushion may have a first wall height in one region of the face and asecond wall height in a second region of the face. Thus more complexshapes may be manufactured.

The filled hollow structure of the present technology may, thus, beproduced in a single moulding tool, obviating handling operations,positioning and/or repositioning of the hollow structure. Therefore, theprocess may be fully automated. Cycle times and production costs may bereduced.

Furthermore, given that the hollow structure does not have to be handledand repositioned, a cleaner look and finish of the overmoulded filledhollow structure may be achieved. Since the filler medium can be fullyencapsulated or enclosed by providing the open hollow structure with theclosing structure the risk of microbes or other unwanted materialsgetting into the cushion and contaminating it can be reduced. Further,forces acting on the bottom or transmission wall of the filled hollowstructure can be distributed evenly, reducing the loads acting on jointsor seams. Leaking risk may thus be minimized. Furthermore, when thefilled hollow structure is attached to means for holding the structureon a patient's head via the support structure, the amount of connectionelements required is reduced, minimizing production costs and the numberof parts requiring disinfection. The technology also allows advantageousdesigns of, e.g., face masks to be established due to the integral andcondensed hollow structure according to the present technology featuringmultiple functionalities in one part, manufactured in one contiguousprocess in one tool.

According to particularly advantageous embodiments of the technology thehollow structure is filled with the filler medium after being at leastpartially closed by provision of the closing structure. In this case theclosing structure may prevent the filler medium from overflowing,allowing, e.g., other means than gravity fill to be employed in order tofill the closed hollow structure. The hollow structure may, thus, befilled more quickly, leading to a more consistent and homogeneous fill.

The closing structure may have barcodes, branding and/or other printedinformation on it. The barcodes, branding and/or printed information maybe internal, i.e., a person would not be able to tamper with it, as itwould be enclosed e.g. by the support structure or the overmoulding.

In an alternative form, an information carrying medium may be embeddedwithin the cushion. For example an RFID or NFC tag could be embeddedwithin the cushion.

The present technology, therefore, overcomes at least some of thedisadvantages of the prior art. In particular, the hollow structure doesnot have to be taken out of the mould and placed on a jig. Formation ofwrinkles and the deformation of the hollow structure is, thus,effectively avoided. Since, the shape of the produced hollow structuresand the volume of the filling material therein is consistent, leading toa manufacturing process that provides reliable results even on a largescale. A further advantage is that the hollow structure can be sealedfrom the surrounding environment during the production processcompletely, preventing creation of microbe traps or contamination areas.

The following aspects are preferred embodiments of the technology.

-   1. A method for producing a filled hollow structure, comprising:    -   producing an open hollow structure from a first material;    -   providing a closing structure to at least partially close the        open hollow structure;    -   filling the hollow structure with a filler medium; and    -   overmoulding the filled hollow structure with a second material.-   2. A method according to aspect 1, wherein the hollow structure is    filled after at least partially closing the open hollow structure    with the closing structure.-   3. A method according to aspects 1 or 2, wherein providing the    closing structure comprises inserting a plug into the open hollow    structure.-   4. A method according to aspect 3, wherein the plug snugly fits into    an opening of the open hollow structure.-   5. A method according to aspects 3 or 4, wherein the plug closes the    open hollow structure.-   6. A method according to aspects 3 to 5, wherein the plug is    preformed or moulded onto the open hollow structure.-   7. A method according to aspects 3 to 6, wherein the plug provides    at least one filling structure, preferably an opening, for filling    the open hollow structure with the filler medium and/or at least one    evacuation structure, preferably an opening, for gas or fluid    evacuation.-   8. A method according to aspects 3 to 7, wherein the plug is    provided with at least one hole for filling the open hollow    structure with the filler medium and/or at least one hole for gas or    fluid evacuation.-   9. A method according to any one of the preceding aspects, wherein    the method comprises multi-component injection moulding.-   10. A method according to any one of the preceding aspects, wherein    the open hollow structure is produced in a cavity of a moulding tool    and remains in a mould half when being closed.-   11. A method according to any one of the preceding aspects, wherein    the hollow structure is produced and closed in a cavity of a    moulding tool and remains in a mould half when being filled.-   12. A method according to any one of the preceding aspects, wherein    the hollow structure is produced, closed and filled in a cavity of a    moulding tool and remains in a mould half when being overmoulded.-   13. A method according to any one of the preceding aspects, wherein    the first material is silicone.-   14. A method according to any one of the preceding aspects, wherein    the closing structure is formed of silicone.-   15. A method according to any one of the preceding aspects, wherein    the second material is silicone, liquid silicone rubber (LSR),    thermoplastic elastomer (TPE), thermoplastic polyurethane (TPU),    thermoplastic vulcanizate (TPV).-   16. A method according to any one of the preceding aspects, wherein    the second material comprises silicone, liquid silicone rubber    (LSR), thermoplastic elastomer (TPE), thermoplastic polyurethane    (TPU), thermoplastic vulcanizate (TPV) and/or the first material.-   17. A method according to any one of the preceding aspects, wherein    the closing structure has a hardness that is higher than the    hardness of the first material and/or higher than the hardness of    the second material.-   18. A method according to any one of the preceding aspects, wherein    the filler medium is a fluid, gas, liquid, foam, expandable fluid,    powder and/or gel.-   19. A method according to any of the preceding aspects, wherein the    filler medium is or comprises silicone, oil, high viscosity fluids,    wax, low viscosity fluids and/or low hardness elastomers.-   20. A method according to any one of the preceding aspects, further    comprising at least partially curing the filler medium.-   21. A method according to any one of the preceding aspects, wherein    the hollow structure is completely or partially filled with the    filler medium.-   22. A method according to any one of the preceding aspects, wherein    the hollow structure comprises a connection adapted to allow a    vacuum or pressure to be applied to the hollow structure.-   23. A method according to aspects 1-22, wherein the tool is heated.-   24. A method according to aspects 1-23, wherein the walls of the    open hollow structure act as an insulating layer to prevent the    filler medium from curing in the hot tool to quickly.-   25. A method according to any one of the preceding aspects, further    comprising providing a support structure between the filler medium    and the second material.-   26. A method according to any one of the preceding aspects, further    comprising providing a support structure between the closing    structure and the second material.-   27. A method according to aspects 25 or 26, wherein the support    structure substantially inhibits contact between the second material    and the filler medium.-   28. A method according to aspects 25-27, wherein the support    structure substantially obstructs at least one opening provided in    the closing structure.-   29. A method according to aspects 25-28, wherein the support    structure is a plastic support member, preferably a rigid plastic    support member.-   30. A method according to aspects 25-29, wherein the material used    for the support structure is harder than the first material and/or    harder than the second material and/or harder than a material used    for the closing structure.-   31. A method according to any one of the preceding aspects, further    comprising providing the hollow structure with further structures to    form a breathing mask.-   32. A method according to any one of the preceding aspects, wherein    the hollow structure is a cushion for a breathing mask.-   33. A method according to aspects 25-32, wherein the support    structure is provided with a connection structure adapted to connect    the hollow structure to a further structure and/or wherein the    support structure is provided with a handling structure adapted for    handling the support structure and/or the hollow structure during    manufacture.-   34. A method according to aspect 33, wherein the connection    structure is adapted to connect the hollow structure to the frame of    a mask and/or to a gear or headgear of a mask assembly.-   35. A method according to aspect 34, wherein the connection    structure comprises lugs for attaching the filled hollow structure    to the frame of a mask.-   36. A method according to any one of the preceding aspects, wherein    the overmoulded second material forms a frame of a mask and/or a    clip for connecting the filled hollow structure to such a frame.-   37. A filled hollow structure comprising    -   an open hollow structure from a first material;    -   wherein the open hollow structure is at least partially closed        by a closing structure;    -   the hollow structure is filled with a filler medium; and    -   the filled hollow structure is overmoulded with a second        material.-   38. A tool for producing a filled structure comprising    -   a first mould half;    -   a second mould half; and    -   a third mould half;    -   wherein the second mould half is configured to form a cavity        with the shape of the negative of an open hollow structure when        mating with the first mould half    -   the first mould half is configured for holding the open hollow        structure while the open hollow structure is at least partially        closed with a closing structure and filled with a filler medium;        and    -   the third mould half is configured to form a cavity with the        shape of the negative of an overmould when cooperating with the        first mould half holding the filled hollow structure-   39. Use of the tool of aspect 38 for producing a filled hollow    structure, preferably a filled hollow structure according to aspect    37, preferably using the method according to any one of aspects    1-36.

Other aspects, features, and advantages of this invention will becomeapparent from the following detailed description when taken inconjunction with the accompanying drawings, which are a part of thisdisclosure and which illustrate, by way of example, principles of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings facilitate an understanding of the variousembodiments of this invention. In such drawings:

FIG. 1 is a schematic view of a production cycle according to anembodiment of a method of the present technology;

FIG. 2 is a cross-sectional view of an open hollow structure accordingto an embodiment of the present technology;

FIG. 3 is a three dimensional exploded view of a filled hollow structureaccording to an embodiment of the present technology;

FIG. 4 is a three dimensional view of a filled hollow structureaccording to an embodiment of the present technology in the assembledstate;

FIG. 5 is a cross-sectional view of an open hollow structure in a toolfor producing the open hollow structure according to an embodiment ofthe present technology;

FIG. 6 is a cross-sectional view of a closed open hollow structure in amould half of a moulding tool for producing said open hollow structure,wherein the open hollow structure has been closed with a closingstructure according to an embodiment of the present technology and isset up for filling;

FIG. 7 is a cross-sectional view of a three dimensional detail of aclosed open hollow structure set up for filling in a mould half of amoulding tool for producing said open hollow structure according to anembodiment of the present technology;

FIG. 8 is a cross-sectional view of a closed and filled open hollowstructure in a mould half of a moulding tool for producing said openhollow structure, wherein the closed and filled open hollow structurehas been provided with a support structure according to an embodiment ofthe present technology;

FIG. 9 is a cross-sectional view of a closed, filled and overmouldedopen hollow structure in a mould half of a moulding tool for producingsaid open hollow structure according to an embodiment of the presenttechnology;

FIG. 10 is a view of a full-face breathing mask 3000 in accordance withthe present technology that is connected to a PAP device 4000 andhumidifier 5000 via an air delivery tube 4170 to provide positive airpressure therapy to a patient 1000.

FIG. 11 shows a patient-side plan view of a cushion 3100 in accordancewith one form of the present technology.

FIG. 12a shows a nasal-bridge end elevation view of a cushion 3100 inaccordance with one form of the present technology illustrating apatient side 3200 of the cushion and a non-patient side 3400 of thecushion 3100.

FIG. 12b shows a chin end elevation view of a cushion 3100 in accordancewith one form of the present technology illustrating a patient side 3200of the cushion and a non-patient side 3400 of the cushion 3100.

FIG. 13 shows a side elevation view of a cushion 3100 in accordance withone form of the present technology illustrating a patient side 3200 ofthe cushion and a non-patient side 3400 of the cushion 3100.

FIG. 14 shows a nasal breathing mask 3000 in accordance with one form ofthe present technology. Also shown is a PAP device 4000, a humidifier5000 and an air delivery conduit 4170.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

In this specification, the word “comprising” is to be understood in its“open” sense, that is, in the sense of “including”, and thus not limitedto its “closed” sense, that is the sense of “consisting of”. Acorresponding meaning is to be attributed to the corresponding words“comprise”, “comprised” and “comprises” where they appear.

In the claims, the term “comprises/comprising” does not exclude thepresence of other elements or steps. Furthermore, although individuallylisted, a plurality of means, elements or method steps may beimplemented. Additionally, although individual features may be includedin different claims, these may possibly advantageously be combined, andthe inclusion in different claims does not imply that a combination offeatures is not feasible and/or advantageous. In addition, singularreferences do not exclude a plurality. The terms “a”, “an”, “first”,“second” etc. do not preclude a plurality.

The invention also covers all further features shown in the figuresindividually although they may not have been described in the aforedescription. Reference signs in the claims are provided merely as aclarifying example and shall not be construed as limiting the scope ofthe claims in any way. The present invention also covers the exactterms, features, values and ranges etc. in case these terms, features,values and ranges etc. are used in conjunction with terms such as about,around, generally, substantially, essentially, at least etc. (i.e.,“about 3” shall also cover exactly 3 or “substantially inhibit” shallalso cover inhibit).

The following description is provided in relation to several preferredembodiments underlying the present invention which will be discussed ina non-limiting way by reference to the Figures in the following. Theembodiments may share common characteristics and features.

FIG. 1 is a schematic view of a method for producing a filled hollowstructure according to an embodiment of the present technology. Inparticular, arrow A indicates the path or successive steps for producinga filled hollow structure according to an embodiment of the method ofthe present technology.

At each position 1 to 4, one or more method steps may be carried outaccording to embodiments of the present technology. In step 1, the openhollow structure or bladder may be produced by injection moulding aplastic structure having thin wall thicknesses from a first material,e.g., silicone (e.g., liquid silicone rubber) in a moulding tool havinga first mould half and a second mould half. The open hollow structuremay then be at least partially closed by providing a closing structuresuch as a plug in step 2 for then being filled with a filler medium instep 3 through a filling structure provided in the closing structure.Subsequently, and optionally, a support may be inserted. As indicated byarrow A, according to embodiments of the method the open hollowstructure may be closed first (forming a closed hollow structure) andfilled subsequently. The now filled hollow structure may then beovermoulded with a second material. The open hollow structure producedin step 1 may remain in the first mould half during steps 2, 3 and 4.The closed filled and overmoulded hollow structure may be taken out orejected from the moulding tool after being overmoulded in step 4.

FIG. 2 illustrates an open hollow structure 11. As illustrated, openhollow structure 11 in an embodiment includes a thin inner wall 18 and athin outer wall 19 wherein a hollow or hollow area 20, such as a pocketor a cavity, is formed between inner wall 18 and outer wall 19. Innerwall 18 and outer wall 19 merge at one end of the structure via a bottomor transition wall 21. Hollow structure 11 may include a closing orsealing area 22, preferably at a side opposite transition wall 21, thatdefines an opening 25 in which the hollow area 20 is open to theenvironment. In the illustrated embodiment, opening 25 is a slotextending around the perimeter of the open hollow structure between theinner wall 18 and the outer wall 19. According to an embodiment, thehollow structure may have a form and/or configuration of face masks fordelivering breathable gas or fluid to a patient and/or of hollowcushions of such masks, e.g., a basically triangular shape when seenfrom above. Depending on the respective application, hollow structure 11may comprise different wall thicknesses as well as various changes ingeometry depending on the individual requirements of the desired use.

FIG. 3 illustrates components of a filled hollow structure 10 accordingto an embodiment of the present technology. The filled hollow structure10 comprises an open hollow structure 11, here in the shape of a cushion3100 of a breathing mask 3000, a closing structure 12, and an overmould15. Optionally, a support structure 14 may be provided.

As shown in FIG. 3, closing structure 12 may be a plug that closes theopening 25 when inserted into closing area 22 of the open hollowstructure 11. Closing structure 12 may snugly or sealingly fit intoopening 25. According to an embodiment, closing structure 12 may havesubstantially the same shape as the hollow structure 11 when viewed fromabove.

As further shown in FIG. 3, overmould 15 may generally follow thecontour of the open hollow structure and/or the contour of the closingstructure. For example, overmould 15 may have substantially the sameshape as the hollow structure and/or the closing structure when viewedfrom above. According to an embodiment, the overmould may have the formand/or configuration of the frame of a mask for delivering breathablegas or fluid to a patient. According to an embodiment, the overmould mayhave the form and/or configuration of a clip for connecting hollowcushions of such masks to a respective frame.

FIG. 4 shows the filled hollow structure 10 according to an embodimentof the present technology in an assembled state. The support structure14 may include lugs 28, 29 for connecting the filled hollow structure toother structures in order to form a breathing mask 3000 or to elementsfor supporting such a mask on a patient's face. For example, lugs 28, 29may be adapted for connecting the filled hollow structure 10 to meansfor fastening a breathing mask 3000 to the face of a patient, e.g. agear or a headgear, an attachment of a forehead support, a frame, or atube connector. Lugs 28, 29 may also be used in order to handle thesupport structure and/or the filled hollow structure duringmanufacturing.

FIG. 5 illustrates the moulding tool 30 during step 1 of FIG. 1 in whichthe open hollow structure 11 is moulded in a cavity of the tool formedby the first mould half 31 when mating with the second mould half 32. Inthis context it should be noted that each of the mould halves maycomprise several parts, inlays, cores, or ejectors pins (not shown),etc. Tool 30 may also comprise ducts and nozzles or channels adapted toapply a vacuum and/or compressed gas or fluid for use in holding hollowstructure 10 on the tool 30 and/or releasing or removing hollowstructure 11 or filled hollow structure 10 from the tool 30.

FIG. 6 illustrates step 2 of FIG. 1 wherein the open hollow structure 11has been moulded and closing structure 12 has been inserted into theopen hollow structure 11. Preferably, closing structure 12 is apreformed plug. However, alternatively or additionally, the closingstructure or plug may also be moulded onto and/or into the open hollowstructure. Closing structure 12 may be a stiff element or ratherflexible and can be made, e.g., from silicone. The closing structure 12may snugly and sealingly fit into the opening 25 and cooperate withsealing area 22 of the open hollow structure to provide a sealingclosure along the perimeter of closing structure 12. As described above,open hollow structure 11 may remain in the first mould half 31 duringinsertion of the closing structure.

According to the present technology the hollow structure may be filledafter closing the open hollow structure with the closing structure. Thisis, the open hollow structure may be first closed and/or sealed with theclosing structure, as discussed above, and subsequently at leastpartially filled with a filler medium. Therefore, when a plug is used asa closing structure, the plug may provide at least one fillingstructure, such as a membrane or opening for filling the open hollowstructure with the filler medium and/or at least one evacuationstructure, such as a self closing membrane or opening for gas or fluidevacuation. E.g. the plug may be provided with at least one hole forfilling the open hollow structure with the filler medium and/or at leastone hole for gas or fluid evacuation.

FIG. 7 shows the hollow structure 11 provided with a closing structure12 with openings or holes 16 set up for filling. Preferably, closingstructure 12 comprises at least one hole 16 for filling the hollow area20 of the hollow structure 11 with the filler medium 13, e.g., via anozzle. According to an embodiment, more than one filler nozzle may beused. Furthermore, closing structure 12 may comprise at least one hole16 for evacuating gas or fluid during filling of the filler medium. Theopenings or holes 16 may be provided at circumferentially opposite sidesof the closing structure 12. As described above, hollow structure 11 mayremain in the first mould half 31 during filling with the filler medium13.

In one form the closing structure 12 has an approximately constantcross-section around its length. In another form, the closing structure12 has a first cross-section in a first region, and a secondcross-section in a second region. In one form the first cross-sectionand the second cross-section are different.

In an embodiment, e.g., when the filler medium is a gel or a siliconegel, the gel may be inserted cold or at room temperature as a liquid andmay be subsequently heated to cure. According to a further embodiment,the gel may be inserted into the hollow area 20 preheated. Thisarrangement allows a faster cure. According to another embodiment, thegel may be inserted pre-cooled into the hollow area 20. This arrangementslows down the curing process, e.g., if the gel is curing too fast. Thegel may be allowed to only cure partially to achieve desired propertiesof the structure. According to an embodiment, mould half 31 may beadapted to assist curing of the filler medium. For example, first mouldhalf 31 may be heatable and/or coolable to allow the filler medium 13filled into hollow area 20 to cure. Additionally, the inner wall 18and/or the outer wall 19 of hollow structure 11 may be adapted in orderto regulate how quickly the filler medium 13 is cured. The filler medium13 may be cured by radiation, e.g., after removing the hollow structurefrom the mould. When a TPE is used as the filler medium 13 or comprisedin the filler medium 13, it may be injected at a high temperature into acold tool.

As a further step, preceding the filling of the hollow area 20 with afiller medium 13, a vacuum may be applied to the hollow area 20 in orderto suck gas or fluid out of the hollow area 20 before the filler medium,such as a gel, is inserted. Preferably, the vacuum is controlled so asto not deform the bladder.

As shown in FIG. 8, hollow structure 11 may optionally be provided withsupport structure 14. Preferably, support structure 14 is provided afterclosing and filling hollow structure 11. In the illustrated embodiment,the support structure 14 comprises protrusions 17. As illustrated,protrusions 17 may be adapted for being inserted into and for closingholes 16 of closing structure 12. Hollow structure 11 may remain inmould half 31 while support structure 14 is provided.

FIG. 9 shows step 4 of FIG. 1 in which the open hollow structure 11 isprovided with an overmould 15 of a second material in a cavity of thetool 30 formed by the second third mould half 33 when mating with thefirst mould half 31 holding the filled and closed hollow structure 11.Third mould half 33 may comprise ducts and nozzles or channels adaptedto apply a vacuum and/or compressed gas or fluid for use in holdinghollow structure 10 on the tool 30 and/or releasing or removing hollowstructure 10 from the tool 30. Furthermore, third mould half 33 maycomprise ejector pins (not shown).

It should be appreciated that the above description as well as thefigures relate to an exemplary embodiment of a method and productaccording to an embodiment of the present technology. However, therespective method as well as the product and tool and, in particular,their geometry should not be considered as being restricted by the aboveexample. According to further embodiments, a hollow structure may nothave a substantially triangular form when viewed from the top and/orbottom. For example, a hollow structure may have a substantiallycircular form. However, the hollow structure may also comprise furthersymmetrical and non-symmetrical forms in top and/or bottom views such asa rectangular, elliptical, round, ring-shaped and/or linear, etc.

As discussed above, the filler medium may be a fluid such as a gaseousand/or liquid medium, a gel, a powder, beats or pellets, foam or afoamable medium, etc. In an embodiment, the filler medium may bestructured to allow the hollow structure to yield or react resilientlyupon application of external pressure and provide a soft and comfortabledeformable appearance. The softness or hardness of the filler medium orthe filled hollow structure may be adapted according to the requirementsof the desired use either during production of the filled hollowstructure or after production and prior to use. This may be establishedby either adjusting the geometry and wall thicknesses of the hollowstructure to adjust the general support of the filler medium, adjustingthe degree up to which the hollow area is filled with the filler medium,adjusting the filler medium itself, as well as a combination of thesefactors. For example, the hollow structure may comprise different wallthicknesses and/or structures for fulfilling additional objects and/orthe like.

In an embodiment, the hollow structure comprises a connection thatallows a vacuum to be applied to the hollow area, thereby allowing thevacuum to deform the hollow structure so that a desired shape may beachieved and maintaining the vacuum in the hollow area after closure ofthe respective connection so that the shape of the hollow structure maybe maintained. Further, a desired shape or individual shape may beformed and fixed by, e.g., a curing process of the filler medium. In anembodiment, the filler medium and thus the filled hollow structure maystill be deformable and soft to a certain degree even after fixation ofa desired shape as discussed above. For example, the hollow structure aswell as the filling may be at least partially flexible and/or may bebrought into a flexible condition.

In an embodiment, the hollow structure may be made of a siliconematerial, e.g., liquid silicone rubber, and the filler medium may alsobe made of a silicone material, e.g., liquid silicone rubber, in asubstantially liquid aggregate state (e.g., such as gel) which may beachieved by partial curing or adding additives. In an embodiment, theovermould may be made of silicone material, e.g., liquid siliconerubber.

In one form of the present technology a breathing mask 3000 comprises acushion 3100 that is connected to a Positive Airway Pressure (PAP)device 4000 and humidifier 5000 via an air delivery tube 4170. In oneform of the present technology CPAP therapy may be delivered to apatient 1000. In another form, other forms of respiratory therapy may bedelivered to a person. In one form the breathing mask 3000 comprises acushion 3100, and a frame 3150 to which the cushion 3100 is connected.In one form the frame 3150 defines part of a plenum chamber. The cushion3100 has a patient side 3200 which is constructed and arranged tocontact a region of a patient's face in use. The cushion 3100 has aframe side 3400 that is constructed and arranged to contact a frame 3150in use. Preferably the frame side 3400 of the cushion is non-planar. SeeFIGS. 12 a, 12 b and 13.

An advantage of the present technology is that it avoids the need forusing a welding process, such as ultrasonic welding. However, anultrasonic welding process may be used if desired.

In an alternative form of the present technology, the over moulding stepis not included, and the combination of filled channel and cap islocated in a clamp, frame or other protective structure.

One advantage of the present technology is that a number of steps may berun in parallel. For example, while one assembly is being over-moulded,one hollow structure may be filled, another may be closed, and a furtherhollow structure may be being moulded. This may reduce cycle time, andlead to higher output.

Another advantage of the present technology is that an open channel maybe created around the entire perimeter of the cushion. Thus, forexample, the whole perimeter may be filled with gel.

Another advantage of the present technology is that it simplifies theprocess for having different amounts of filler medium in differentportions of the hollow structure. For example, when the closingstructure has first- and second-crosssections in different regions, thecorresponding complementary amount of filler medium may be different inthose different regions.

While the invention has been described in connection with what arepresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiments, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the invention. Also, the various embodiments described abovemay be implemented in conjunction with other embodiments, e.g., aspectsof one embodiment may be combined with aspects of another embodiment torealize yet other embodiments. Further, each independent feature orcomponent of any given assembly may constitute an additional embodiment.In addition, while the invention has particular application to patientswho suffer from OSA, it is to be appreciated that patients who sufferfrom other illnesses (e.g., congestive heart failure, diabetes, morbidobesity, stroke, bariatric surgery, etc.) can derive benefit from theabove teachings. Moreover, the above teachings have applicability withpatients and non-patients alike in non-medical applications.

Table of Part and Step references Part or step Reference Moulding openhollow structure 1 Closing open hollow structure 2 Filling closed hollowstructure 3 Overmoulding 4 Filled hollow structure 10 Open hollowstructure 11 Closing structure 12 Filler medium 13 Support structure 14Overmould 15 Openings or holes 16 Protrusions 17 Inner wall 18 Outerwall 19 Hollow area 20 Transition wall 21 Closing area 22 Opening 25 Lug28 Lug 29 Tool 30 First mould half 31 Second mould half 32 Third mouldhalf 33 Patient 1000 Breathing mask 3000 Cushion 3100 Frame 3150 Patientside 3200 Frame side 3400 PAP device 4000 Air delivery tube 4170Humidifier 5000

1. A filled hollow structure comprising an open hollow structure from afirst material; wherein the open hollow structure is at least partiallyclosed by a closing structure; the hollow structure is filled with afiller medium; and the filled hollow structure is overmoulded with asecond material.
 2. A tool for producing a filled structure comprising afirst mould half; a second mould half; and a third mould half; whereinthe second mould half is configured to form a cavity with the shape ofthe negative of an open hollow structure when mating with the firstmould half the first mould half is configured for holding the openhollow structure while the open hollow structure is at least partiallyclosed with a closing structure and filled with a filler medium; and thethird mould half is configured to form a cavity with the shape of thenegative of an overmould when cooperating with the first mould halfholding the filled hollow structure.
 3. A filled hollow structurecomprising an open hollow structure from a first material; wherein theopen hollow structure is at least partially closed by a closingstructure; the hollow structure is filled with a filler medium; and thefilled hollow structure is overmoulded with a second material, whereinthe closing structure has a hardness that is higher than the hardness ofthe first material and/or higher than the hardness of the secondmaterial.
 4. The filled hollow structure according to claim 3, whereinthe closing structure's hardness is higher than the hardness of thefirst material and the second material.
 5. The filled hollow structureaccording to claim 3, wherein the hollow structure has a patient sideseal which is constructed and arranged to contact a region of apatient's face in use.
 6. The filled hollow structure according to claim5, wherein the hollow structure defines an opening to receive at leastpart of the patient's nose in use, and the seal extends inwards towardsthe opening.
 7. The filled hollow structure according to claim 3,wherein the hollow structure when filled with the filler medium isdeformable.
 8. The filled hollow structure according to claim 3, furthercomprises a plug to close the open hollow structure, wherein the plughas a side wall surface that directly engages a side wall surface of thehollow structure.
 9. The filled hollow structure according to claim 8,wherein the opening extends substantially parallel to the sidewallsurface of the plug and the sidewall surface of the hollow structure.10. The filled hollow structure according to claim 8, wherein the plughas a central portion with a first height and the sidewall surface has asecond height greater than the first height.
 11. The filled hollowstructure according to claim 8, wherein the plug directly engages theside wall surface.
 12. The filled hollow structure according to claim 8,wherein the plug provides at least one filling structure, including anopening, for filling the open hollow structure with the filler mediumand/or for evacuating the filler medium from the hollow structure. 13.The filled hollow structure according to claim 3, wherein the firstmaterial is silicone.
 14. The filled hollow structure according to claim13, wherein the closing structure is formed of silicone.
 15. The filledhollow structure according to claim 3, wherein the second material issilicone, liquid silicone rubber (LSR), thermoplastic elastomer (TPE),thermoplastic polyurethane (TPU), thermoplastic vulcanizate (TPV). 16.The filled hollow structure according to claim 3, wherein the secondmaterial comprises silicone, liquid silicone rubber (LSR), thermoplasticelastomer (TPE), thermoplastic polyurethane (TPU), thermoplasticvulcanizate (TPV) and/or the first material.
 17. The filled hollowstructure according to claim 3, wherein the filler medium is a fluid,gas, liquid, foam, expandable fluid, powder and/or gel.
 18. The filledhollow structure according to claim 3, wherein the hollow structure iscompletely or partially filled with the filler medium.
 19. The filledhollow structure according to claim 3, wherein the hollow structurecomprises a connection adapted to allow a vacuum or pressure to beapplied to the hollow structure.
 20. The filled hollow structureaccording to claim 3, wherein the support structure is provided with aconnection structure including lugs adapted to attach the filled hollowstructure to a frame of a respiratory mask.